Stone tools dating back 2.5 million years are the oldest ever found,
scientists reported Wednesday, prompting a search for more evidence
about the pre-humans who made them. The surprisingly sophisticated
tools, found on the border between Ethiopia and Kenya, push back the
frontier of the first-known use of tools by pre-humans by 200,000
years. Sileshi Semaw of Rutgers University in New Jersey and
colleagues say the tools are considerably older than others found in
the region, which date back 2.3 million years. For the full text
story, see http://www.merc.com/stories/cgi/story.cgi?id=1211896-169